Alchemist can call Hohenheim Guardian. Hohenheim increases the summoners magic defense and allows the usage of exclusive skills such as Acid Terror that delivers powerful melee and magic damage at the same time.

Artisan can summon Veriel. Veriel significantly increases the summoners flee and allows the usage of exclusive skills such as Shining Gimlet that afflicts quick continuous damage on far away enemies.

Blacksmith can call Vulcan. Vulcan increases the summoners melee defense and allows the usage of exclusive skills such asHammerfall which decreases the enemies defense.

Chef can summon Demeter. Demeter greatly increases the summoners HP auto-recovery and allows the usage of exclusive skills such as Lusty Smell which poisons enemies with a powerful poison.

Alchemist can call Hohenheim Guardian. Hohenheim increases the summoners magic defense and allows the usage of exclusive skills such as Acid Terror that delivers powerful melee and magic damage at the same time.

Artisan can summon Veriel. Veriel significantly increases the summoners flee and allows the usage of exclusive skills such as Shining Gimlet that afflicts quick continuous damage on far away enemies.

Blacksmith can call Vulcan. Vulcan increases the summoners melee defense and allows the usage of exclusive skills such asHammerfall which decreases the enemies defense.

Chef can summon Demeter. Demeter greatly increases the summoners HP auto-recovery and allows the usage of exclusive skills such as Lusty Smell which poisons enemies with a powerful poison.

Give the Magic Oils to Chefs! Because they desperately need something...and it makes more sense to have Chefs make oils? I don't know Alchemists are useful as is though. Or maybe allow them to refine Dim Crystals -> Radiant Crystals -> Mysterious Crystals? Since they know chemistry...

Alchemist can call Hohenheim Guardian. Hohenheim increases the summoners magic defense and allows the usage of exclusive skills such as Acid Terror that delivers powerful melee and magic damage at the same time.Artisan can summon Veriel. Veriel significantly increases the summoners flee and allows the usage of exclusive skills such as Shining Gimlet that afflicts quick continuous damage on far away enemies.Blacksmith can call Vulcan. Vulcan increases the summoners melee defense and allows the usage of exclusive skills such asHammerfall which decreases the enemies defense.Chef can summon Demeter. Demeter greatly increases the summoners HP auto-recovery and allows the usage of exclusive skills such as Lusty Smell which poisons enemies with a powerful poison.

I don't think the OP was talking about the guardians though, since guardians already have their combat uses regardless of their job.

The issue is more that once you reach endgame, there's not all that much to do with your profession if you don't have epic recipes, so what do the lay-people who don't have the epic recipes do with their profession? This is in the blacksmith section, so for example: If you don't have the epic-gear recipes all you really have for crafting are Rune Punchers, and those are commonly awarded from Colosseum boxes. And let's not even talk about Chefs; I haven't cooked anything in over a month because I'm swimming in hourly/daily reward food.